The Garmin Charging & Data USB Cable is compatible with the Forerunner 645 and 645 Music models of Garmin GPS smartwatches. It can charge your Forerunner when connected to a USB power source, such as a computer's USB port, a USB AC adapter, or power bank. When connected to a computer's USB port, you gain the additional ability to transfer data to and from the Forerunner and your computer.